Chickpeas, beans, lentils or peas can keep away "bad cholesterol" with just one serving per day, according to a new study published in CMAJ.
Low-density lipoprotein (LDL) cholesterol is one of the most important risk factors for cardiovascular disease. The reason for its importance? Because it can be avoided by simple dietary modifications.
Non-oil-seed pulses, such as beans, chickpeas, lentils and peas, are already recommended as part of dietary guidelines to prevent major chronic diseases. A large observational study has also linked consumption of these pulses with lower LDL cholesterol levels.
The new study, by Canadian researchers at St. Michael's Hospital, Toronto, was intended to improve the evidence on which these dietary guidelines are based.
To do this, the researchers conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) assessing the effects of pulse consumption on reducing LDL cholesterol.
The review drew its data from 26 RCTs, looking at 1,037 people altogether. Overall, the review found that people who ate one serving (3/4 cup) of non-oil-seed legumes a day exhibited a 5% reduction in LDL cholesterol.
"The reduction of 5% [LDL cholesterol] in our meta-analysis suggests a potential risk reduction of 5-6% in major vascular events," writes co-author Dr. John Sievenpiper.
The study also found a greater reduction in LDL cholesterol in men than women. The researchers think this might be because men generally have poorer diets and higher cholesterol than women, so they show greater improvements from a healthier diet.
Despite the reduction in LDL cholesterol, some participants did experience minor side effects from the diet, such as bloating, flatulence, diarrhea or constipation. However, the researchers write that the suggested one serving a day "is currently consumed by many cultures without reports of adverse effects that would limit consumption."
North Americans 'have a lot of room in their diets to increase pulse intake'
People who ate one serving (3/4 cup) of non-oil-seed legumes a day exhibited a 5% reduction in LDL cholesterol.
The researchers acknowledge though that legume intake in many Western countries, such as Canada and the US, is quite low.
"Canadians have a lot of room in their diets to increase their pulse intake and derive cardiovascular benefits," states Dr. Sievenpiper. "Only 13% consume pulses on any given day, and of those who do, the average intake is only about a half serving."
As well as improving LDL cholesterol, the researchers also believe that eating legumes every day could have other beneficial effects that may protect against cardiometabolic problems. These could include improving body weight, blood pressure and glucose control.
However, this study had some limitations. The study periods of the RCTs within this systematic review were all shorter than 3 months and did not report enough data to safeguard against a risk of bias. More high-quality evidence is needed to confirm the positive effects of legumes in lowering LDL cholesterol.
"Future systematic reviews and meta-analyses should evaluate the effects of such dietary interventions on these outcomes and others, to address factors that contribute to residual cardiovascular disease risk," the authors conclude.
In 2013, Medical News Today reported on a study that found levels of LDL cholesterol are linked to brain deposits that cause Alzheimer's disease.